/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 * Messaging support.  To minimize ld.so.1's overhead, messaging support isn't
 * enabled until we need to contruct a message - Note that we don't rely on the
 * application to signify whether messaging is applicable, as many message
 * conditions (such as relocations) are generated before the application gains
 * control.
 *
 * This code implements a very trimmed down version of the capabilities found
 * via setlocale(3c), textdomain(3i) and gettext(3i).  Dragging in the original
 * routines from libc/libintl isn't possible as they cause all i18n support to
 * be included which is far too expensive for ld.so.1.
 */

#include <sys/types.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <limits.h>
#include <libintl.h>
#include "_rtld.h"
#include "msg.h"

/*
 * A message object file (as generated by msgfmt(1)) consists of a message
 * header, followed by a message list, followed by the msgid strings and then
 * the msgstr strings.  None of this is defined in any OSNET available headers
 * so we have our own local definitions :-(
 */
typedef struct {
	int	hdr_midlst;		/* middle message no. */
	int	hdr_lstcnt;		/* total no. of message in the file */
	int	hdr_msgidsz;		/* size of msgids (in bytes) */
	int	hdr_msgstrsz;		/* size of msgstrs (in bytes) */
	int	hdr_lstsz;		/* size of message list (in bytes) */
} Msghdr;

typedef struct {
	int	lst_less;
	int	lst_more;
	int	lst_idoff;
	int	lst_stroff;
} Msglst;

#define	LEAFINDICATOR		-99
#define	OLD_MSG_STRUCT_SIZE	20
#define	NEW_MSG_STRUCT_SIZE	(sizeof (Msglst))

/*
 * Define a local structure for maintaining the domains we care about.
 */
typedef struct {
	const char	*dom_name;
	const Msghdr	*dom_msghdr;
	size_t		dom_msgsz;
} Domain;


/*
 * Perform a binary search of a message file (described by the Msghdr) for a
 * msgid (string).  Given a match return the associated msgstr, otherwise
 * return the original msgid.
 */
static const char *
msgid_to_msgstr(const Msghdr *msghdr, const char *msgid)
{
	const Msglst	*list, *_list;
	const char	*ids, *strs, *_msgid;
	int		off, var;

	/*
	 * Establish pointers to the message list (we actually start the search
	 * in the middle of this list (hdr->midlst), the msgid strings (ids)
	 * and the msgstr strings (strs).
	 */
	list = (const Msglst *)&msghdr[1];
	ids = (const char *)&list[msghdr->hdr_lstcnt];
	strs = (const char *)&ids[msghdr->hdr_msgidsz];

	off = msghdr->hdr_midlst;

	for (;;) {
		_list = list + off;
		_msgid = ids + _list->lst_idoff;

		if ((var = strcmp(_msgid, msgid)) == 0)
			return (strs + _list->lst_stroff);

		if (var < 0) {
			if ((off = _list->lst_less) == LEAFINDICATOR)
				return (msgid);
		} else {
			if ((off = _list->lst_more) == LEAFINDICATOR)
				return (msgid);
		}
	}
	/* NOTREACHED */
	return (NULL);	/* keep gcc happy */
}

/*
 * Open a message file. Following the model of setlocale(3c) we obtain the
 * message file for the specified locale.  Normally this is:
 *
 *	/usr/lib/locale/`locale'/LC_MESSAGES/`domain'.mo
 *
 * The locale was determined during initial environment processing (see
 * readenv()), which was determined from an LC_ALL, LC_MESSAGES or LANG
 * setting.  If no locale has been specified, or any file processing errors
 * occur, internationalization is basically disabled.
 */
static void
open_mofile(Domain * dom)
{
	const char	*domain = dom->dom_name;
	char		path[PATH_MAX];
	int		fd;
	rtld_stat_t	status;
	const Msghdr	*msghdr;
	int		count;
	size_t		size_tot, size_old, size_new;

	dom->dom_msghdr = (Msghdr *)-1;

	(void) snprintf(path, PATH_MAX, MSG_ORIG(MSG_FMT_MSGFILE),
	    glcs[CI_LCMESSAGES].lc_un.lc_ptr, domain);

	if ((fd = open(path, O_RDONLY, 0)) == -1)
		return;

	if ((rtld_fstat(fd, &status) == -1) ||
	    (status.st_size < sizeof (Msghdr))) {
		(void) close(fd);
		return;
	}

	/* LINTED */
	if ((msghdr = (Msghdr *)mmap(0, status.st_size, PROT_READ, MAP_SHARED,
	    fd, 0)) == (Msghdr *)-1) {
		(void) close(fd);
		return;
	}
	(void) close(fd);

	/* checks if opened file is msg file */

	count = msghdr->hdr_lstcnt;
	if (((count - 1) / 2) != msghdr->hdr_midlst) {
		(void) munmap((caddr_t)msghdr, status.st_size);
		return;
	}

	size_tot = msghdr->hdr_lstsz;
	size_old = OLD_MSG_STRUCT_SIZE * count;
	size_new = (int)NEW_MSG_STRUCT_SIZE * count;
	if ((size_tot != size_old) && (size_tot != size_new)) {
		(void) munmap((caddr_t)msghdr, status.st_size);
		return;
	}

	size_tot = msghdr->hdr_msgidsz + msghdr->hdr_msgstrsz +
	    (int)sizeof (Msghdr);
	if ((size_tot + size_old < status.st_size) &&
	    (size_tot + size_new < status.st_size)) {
		(void) munmap((caddr_t)msghdr, status.st_size);
		return;
	}

	/*
	 * We have a good message file, initialize the Domain information.
	 */
	dom->dom_msghdr = msghdr;
	dom->dom_msgsz = status.st_size;
}


/*
 * Two interfaces are established to support our internationalization.
 * gettext(3i) calls originate from all link-editor libraries, and thus the
 * SUNW_OST_SGS domain is assumed.  dgettext() calls originate from
 * dependencies such as libelf and libc.
 *
 * Presently we support two domains (libc's strerror() uses SUNW_OST_OSLIB).
 * If ld.so.1's dependencies evolve to require more then the `domain' array
 * maintained below can be enlarged or made more dynamic in nature.
 */
char *
dgettext(const char *domain, const char *msgid)
{
	static int	domaincnt = 0;
	static Domain	*domains;
	Domain		*_domain;
	int		cnt;

	if (glcs[CI_LCMESSAGES].lc_un.lc_val == 0)
		return ((char *)msgid);

	/*
	 * Determine if we've initialized any domains yet.
	 */
	if (domaincnt == 0) {
		if ((domains = calloc(sizeof (Domain), 2)) == NULL)
			return ((char *)msgid);
		domains[0].dom_name = MSG_ORIG(MSG_SUNW_OST_SGS);
		domains[1].dom_name = MSG_ORIG(MSG_SUNW_OST_OSLIB);
		domaincnt = 2;
	}

	/*
	 * If this is a new locale make sure we clean up any old ones.
	 */
	if (rtld_flags & RT_FL_NEWLOCALE) {
		cnt = 0;

		for (_domain = domains; cnt < domaincnt; _domain++, cnt++) {
			if (_domain->dom_msghdr == 0)
				continue;

			if (_domain->dom_msghdr != (Msghdr *)-1)
				(void) munmap((caddr_t)_domain->dom_msghdr,
				    _domain->dom_msgsz);

			_domain->dom_msghdr = 0;
		}
		rtld_flags &= ~RT_FL_NEWLOCALE;
	}

	/*
	 * Determine which domain we need.
	 */
	for (cnt = 0, _domain = domains; cnt < domaincnt; _domain++, cnt++) {
		if (_domain->dom_name == domain)
			break;
		if (strcmp(_domain->dom_name, domain) == 0)
			break;
	}
	if (cnt == domaincnt)
		return ((char *)msgid);

	/*
	 * Determine if the domain has been initialized yet.
	 */
	if (_domain->dom_msghdr == 0)
		open_mofile(_domain);
	if (_domain->dom_msghdr == (Msghdr *)-1)
		return ((char *)msgid);

	return ((char *)msgid_to_msgstr(_domain->dom_msghdr, msgid));
}

/*
 * This satisfies any dependencies of code dragged in from libc, as we don't
 * want libc's gettext implementation in ld.so.1.  This routine may not be
 * referenced, in which case -zignore will discard it.
 */
char *
gettext(const char *msgid)
{
	return ((char *)dgettext(MSG_ORIG(MSG_SUNW_OST_SGS), msgid));
}

/*
 * The sgsmsg.1l use requires the following interface.
 */
const char *
_rtld_msg(Msg mid)
{
	return ((char *)dgettext(MSG_ORIG(MSG_SUNW_OST_SGS), MSG_ORIG(mid)));
}
